1. Field of the Invention
The present invention relates to a brace or top stick rotating mechanism, and more particularly, to a brace rotating mechanism capable of preventing the lid or top board of a musical instrument such as a grand piano from inadvertently rotating.
2. Background Art
A Grand piano having a lid that is supported as to be able to be opened and closed on the top of a piano body has been widely used in the past. Known grand pianos are provided with an arm-like brace that maintains the piano lid in the opened state, and the brace is provided so as to be able to rotate between an erect position and a collapsed position. In order to allow this brace to adjust the opening angle of the lid in steps, two or three types of braces of varying lengths are provided. In addition, two receptacles capable of holding the end of these braces corresponding to each brace are attached in a row on the underside of the lid, and each receptacle is provided at a relative position at which the plane of the lid in the open position and axis of the brace are roughly perpendicular.
The task of holding the open position of the lid is performed by maintaining the open position of the lid with one hand while rotating the brace in the direction in which it becomes erect with the other hand, followed by placing the end of the brace in the corresponding receptacle so that the lid rests on the brace.
However, in the case of maintaining the open position of the lid, it is necessary to rotate the lid and brace roughly simultaneously in order to place the end of the brace in the receptacle. At this time, since the lid is quite heavy, the hand holding the lid can easily become shaky, resulting in the problem of the end of the brace shifting out of a position to a state in which it is not reliably held in the receptacle, and this becomes a factor that induces inadvertent rotation of the lid. In addition, since two receptacles are attached in a row, it is feared that the end of the brace is placed in the non-corresponding receptacle. When the end of the brace is placed in the receptacle in such a state, the open position of the lid becomes unstable due to the angle between the plane of the lid and the axis of each brace no longer being maintained roughly perpendicular, and as a result, the lid may end up closing due to an inadvertent impact and so forth, leading to the problem of causing a malfunction or damage to the grand piano.
However, there are some grand pianos that are provided with a contactable stopper at the base of the brace in order to facilitate the task described above. When the brace is put in the erect position in which it holds the lid, this stopper makes contact with the base of the brace and is provided so as to be able to maintain the angle of rotation of the brace by supporting this contact state by hand.
However, in the case of using such a stopper, since the brace ends up collapsing if force that presses the base of the brace against the stopper, namely force that rotates the brace in the direction of becoming upright, is not applied, the brace must unavoidably be supported with one hand. Thus, this leads to the problem of being unable to use both hands to perform the task of lifting up the lid with both hands.